1. Technical Field
This disclosure relates to lighting tube fittings and structures with specific application to custom made lighting tube holding devices.
2. Background Art
Holders for lighting tubes are known in the art. For example, various conventional fittings for holding neon tubes are illustrated and described in U.S. Pat. No. 4,947,301 to Charles Steele, entitled “Neon Tube Electrode Housing,” issued Aug. 7, 1990, the disclosure of which is hereby incorporated by reference.
Gas filled lighting tubes (tubes) became popular as the well known neon advertisement signs and have evolved into the familiar fluorescent tubes of standard lengths used in businesses and homes ubiquitously. These tubes are typically designed with two electrodes at each end and standard electrical fittings and plugs have been designed to facilitate the use of these tubes everywhere. Although gas filled lighting has been standardized in many aspects, custom lighting tubes still exists. Custom made lighting tubes continue to be used for advertisement and other target locations in a home or business where unique lighting is desired. These custom made lighting tubes typically include the standard two prong electrodes at each end of the tube connected to a power source that subsequently ionizes a gas within the tube to create luminescence.
One of the principle challenges of installing custom made lighting tubes in a sign or for other use is mounting of the lighting tubes on a fascia or within lighting housing. Each tube is generally a piece of custom glass work and the tube is formed in a particular shape with the electrodes of the tube designed for a targeted dimension to correspond with and be parallel with each other. The custom glass work, however, because each tube is manufactured separately, does not always align properly with the electrode holders and there exists the potential for the tube electrodes to not align properly with sign housing fixtures.
Because of the specific tolerances that must generally be met for a tube to attach to a conventional sign, it is not uncommon for the electrode ends to not be exactly parallel. Where a replacement lighting tube is manufactured to fit an existing lighting display, the alignment with both the electrode holders and with the existing tube supports may be desired but is difficult to achieve. The new lighting tube will often break during the installation process as an installer attempts to align the rigid glass tube into an existing support. In addition, once conventional tubes are installed in a sign, the tube is generally quite rigidly fixed in place, and there can be little or no adjustment of the positions of the electrodes. Because of this, an installer generally cannot perform any, or can only perform very few, adjustments of the electrode positions of the tube after installation to adapt to particular tube holders. Also, because the tube is rigidly fixed, thermal expansion stresses on the tube during seasonal operation can be significant, particularly if the electrode was installed touching one of the surfaces of the housing. In addition, because the tube supports are located along the surface of the sign, conventional tubes are manufactured to produce shapes within a single plane that is parallel with a back wall of the sign housing, allowing them to be within reach of the tube supports.